Major efforts included: (1) assisting members of the Viral Epidemiology Section on the design and analysis of studies of the natural history of HIV infection and of biological markers in hemophiliacs and infants; (2) estimating the numbers infected with HIV through mid 1987 by backcalculation; (3) extending earlier work showing that treatment had a favorable impact on national AIDS incidence trends among homosexual men to various other exposure groups; (4) analyzing the joint effects of radon, arsenic and tobacco products on the risk of lung cancer; (5) editing data and preparing analysis files to further quantitate these relationships based on large case-control and cohort studies of lung cancer in Gejiu, China; (6) analyzing the risk of thyroid nodules and thyroid cancer following radiation to the head and neck; (7) studying the impact, of treatments for childhood cancer on the risk of early menopause; (8) evaluating DNA fingerprints as an aid to identifying contamination of tissue cultures; (9) developing methods and tables for projecting individualized risks of breast cancer over a given age range for women with specific risk factors(10) monitoring clinical trials of nutritional supplements to prevent cancer, of, interventions to prevent smoking, and of therapies to prevent AIDS among infected groups; and (11) providing consultation on the use of newly developed computing packages for epidemiologic analysis.